Specifications; Timing Table & Definitions - White Rodgers 21V51U-843 Installation Instructions Manual

Integrated two-stage/variable speed motor hot surface ignition control kit
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SPECIFICATIONS

ELECTRICAL RATINGS [@ 77°F (25°C)]:
Input Voltage: 25 VAC, 60 Hz (Class II transformer required)
Max. Input Current @ 25 VAC: 500mA + MV
Relay Load Ratings:
Gas Valve Relays: 1.5 amps @ 25 VAC, 60 Hz
Inducer Relays: 2.2 FLA - 3.5 LRA @120 VAC
Ignitor Relay: 4.0 amps @ 120 VAC (Resistive)
Humidifier/EAC: 120 VAC/1 Amp
Flame Current Requirements:
Minimum current to insure flame detection: 0.3 µa DC*
Maximum current for non-detection: 0.1 µa DC*
Maximum allowable leakage resistance: 100 M ohms
*Measured with a DC microammeter in the flame probe lead
Event
Pre-purge Time
Igniter Warm-up Time
Trial for Ignition Period (TFI)
Ignition Activation Period (IAP)
Retries
Valve Sequence period
Inter-purge
Post-purge Time
Lock-Out Time
Heat Delay-To-Fan-On
Heat Delay-To-Fan-Off*
Cool Delay-To-Fan-On
Cool Delay-To-Fan-Off
Automatic Reset Time
*These times will vary depending on option switch position.
2
21V51U-843 TIMING TABLE
(All times are in seconds, unless noted otherwise)
The period of time intended to allow for the dissipation of any unburned
gas or residual products of combustion at the beginning of a furnace
operating cycle prior to initiating ignition
The length of time allowed for the igniter to heat up prior to the initiation
of gas flow.
The period of time between initiation of gas flow and the action to
shut off the gas flow in the event of failure to establish proof of the
supervised ignition source or the supervised main burner flame.
The period of time between energizing the main gas valve and
deactivation of the ignition means prior to the end of TFI
The additional attempts within the same thermostat cycle for ignition
when the supervised main burner flame is not proven within the first
trial for ignition period.
Valve sequence period equals 4 seconds trial for ignition period x
(1 initial try + 2 retries) + 12 seconds.
The period of time intended to allow for the dissipation of any unburned
gas or residual products of combustion between the failed trial for
ignition and the retry period.
The period of time intended to allow for the dissipation of any unburned
gas or residual products of combustion at the end of a furnace burner
operating cycle. Post-purge begins at the loss of flame sense.
ANSI standard rated module timing.
The period of time between proof of the supervised main burner flame
and the activation of the blower motor at Heat speed.
The period of time between the loss of a call for heat and the
deactivation of the blower motor at Heat speed.
The period of time after a thermostat demand for cool before
energizing the circulator blower motor at Cool speed.
The period of time between the loss of a call for cool and the
deactivation of the blower motor at Cool speed.
After one (1) hour of internal or external lockout, the control will
automatically reset itself and go into an auto restart purge for 60
seconds.
OPERATING TEMPERATURE RANGE:
-40° to 175°F (-40° to 80°C)
HUMIDITY RANGE:
5% to 93% relative humidity (non-condensing)
Timing Specs: (@ 60 Hz)
Flame Establishing Time:
Flame Failure Response Time:
Gases Approved: Natural, Manufactured, Mixed, Liquefied
Petroleum, and LP Gas Air Mixtures are all approved for use.
Definition
maximum
0.8 sec
2.0 secs
50M51-843
15
17
4
3
2 times
12
60
15
300
45
90/120/150/180
5
60
60 minutes

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